textproduct: Albany

WHAT HAS CHANGED

UPDATE - 10:55 AM EDT...Quick update this morning to mention the convective complex currently tracking through central NY. This is expected to track E/SE along the low-level thermal gradient through the next few hours. Very little instability across our region per latest SPC mesoanalysis, and we are already seeing weakening trends on IR satellite imagery. That said, some briefly heavy showers may scrape the western Mohawk Valley or western Catskills late this morning through early to mid afternoon. Probability for hydro issues looks low given expected weakening trend, but will be increasing PoPs in these areas through the next few hours. Bigger threat for some severe and localized flash flooding appears to be this evening into tonight with another MCS expected to track across our region. Otherwise, please see previous discussion below for more details...

KEY MESSAGES

1) Rain showers and thunderstorms expected this afternoon into tomorrow morning across eastern New York and western New England. A few storms could become severe this afternoon across the southwest Adirondacks, Mohawk Valley, and eastern Catskills with damaging winds the primary concern.

2) Isolated instances of flash flooding due to periods of heavy rainfall tonight into Thursday morning across portions of eastern New York and western New England.

DISCUSSION

KEY MESSAGE 1... While the morning hours begin dry across eastern New York and western New England, rain shower and thunderstorm activity increases this afternoon from west to east. The Marginal Risk (level 1 of 5) has not changed from yesterday's Day 2 Severe Weather Outlook by the Storm Prediction Center (SPC) which now became Day 1 that includes the southwestern Adirondacks, Mohawk Valley, and eastern Catskills. Let's talk about what could happen this afternoon into this evening. There are two different scenarios that can happen across the southwestern Adirondacks, western Mohawk Valley, and eastern Catskills. They are both highly dependent on what the stationary front to our west will do with the surface low pressure system.

Scenario Number One: The front stalls way to our west and no severe storms develop. This prevents significant warm air arriving with enough time for surface heating to occur. While only one high resolution model guidance shows this, depending on how this morning's environmental conditions exist this scenario shows there could be lacking all necessary ingredients for severe storms to develop (similarly to what happened yesterday) across the southwestern Dacks, Mohawk Valley, and eastern Catskills.

Scenario Number Two: The front does not stall and we see a few severe storms across southwestern Adirondacks, western Mohawk Valley, and eastern Catskills. This scenario supports warm air arriving to these locations for sufficient surface heating. Additionally, there are enough ingredients for a few severe storms to develop in these locations based on the other high resolution forecast model guidances. The most likely timing for thunderstorms to develop and move into these locations is after noon and through the late afternoon hours. How exactly the storms will be is still the tricky part to today's forecast as a few could develop into a line of storms, while the rest remain isolated in nature.

The current forecast supports scenario number two, but we can't ignore scenario number 1 for this afternoon into this evening for how the severe weather threat could play out. Forecast confidence continues to be low for this afternoon into this evening based on the disagreements of the high resolution forecast models and current environment. While they continue to be in disagreement for how to environment will play out with the warm front and if we have enough ingredients needed for storms to become severe, if a severe storm does develop then the primary concern is going to be damaging wind gusts. Continue to monitor latest SPC severe weather outlooks for today's environment and have multiple ways to receive warnings.

KEY MESSAGE 2...

The second concern today with rain showers and thunderstorms is heavy rainfall across eastern New York and western New England. While not everyone will see a severe thunderstorm today, even with non-severe thunderstorms heavy rain is a concern as the environment is favorable. Latest high resolution forecast model guidances support the necessary ingredients needed for heavy downpours associated with rain showers and thunderstorms from late this afternoon into the overnight hours tonight. Latest probabilities for rainfall totals over 1 inch in the next 24 hours are greater than 75 percent for locations north and west of Albany. The ground is saturated from yesterday's rainfall. And if any location sees repeated heavy downpours this evening into tonight, isolated instances of flash flooding could occur. Especially for locations that have typical poor drainage and ponding on roadways. Small stream/creeks could rise.

Across portions of the Mohawk Valley, scattered instances of flash flooding have low chances of occurring this evening, but the risk is there as repeated rounds of rain showers and/or thunderstorms could occur tonight into Thursday morning. Rainfall totals for today through tomorrow will greatly depend on who sees the heaviest rainfall and where repeated rain showers and thunderstorms develop this afternoon into tonight. Confidence has increased for the chances of rain showers and thunderstorms this afternoon and into the overnight hours, so medium to high chances are in store across eastern New York and western New England through the early morning hours Thursday.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

As of 18 UTC/02, widespread MVFR cigs continue with an area of showers tracking from west to east through ALB and POU. These showers look to reach PSF shortly after 18 UTC with a few brief showers near GFL. A thunderstorm is just south of POU so included VCTS for this site only through 21 UTC. Showers diminish by 20 - 21 UTC from west to east with a brief for dry weather through early evening with cigs at GFL and ALB even trending upwards back to VFR for a period. However, guidance remains in good agreement with an organized area of rain and embedded thunderstorms tracking from western/central NY eastward reaching ALB/GFL first followed by PSF/POU next between 03 - 06 UTC. While instability will be elevated, there is enough evidence that rumbles of thunder and periods of moderate to heavy rain can occur at all terminals for a brief window so include a TEMPO group from 03 - 08 UTC tonight that result in IFR cigs and vis. The heaviest rain and any storms should end by 07-08 UTC with lingering rain showers ending from northwest to southeast by 09 - 11 UTC. Cigs at GFL/PSF look to drop IFR during this period while ALB/POU cigs should return to MVFR. IFR cigs at PSF/GFL should improve to MVFR towards the end of the TAF period with VFR conditions likely returning to all terminals shortly after the TAF period ends.

Southeasterly winds 5-12kts with gusts up to 15-20kts through this evening shift to the west - northwest as the area of rain and embedded thunderstorms pushes through the terminals overnight. Westerly winds continue through the end of the TAF period sustained 5-10kts with gusts up to 15kts.

Outlook...

Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: Low Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Labor Day: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.